| 摘要 |
<p>PURPOSE:To change the pitch of recorded or reproduced sounds to fast or slowly reproduce sounds by changing the frequency of a cylinder rotation synchronizing signal and the tape speed in proportion to a sampling clock frequency. CONSTITUTION:A sampling clock 8, a cylinder rotation synchronizing signal 10, a rotative speed reference signal 15, and a synchronizing signal detecting and counting clock 28 of an ATF signal for tracking servo are generated based on a single master clock by a PLL (phase locked loop) circuit and frequency dividers. Consequently, when the frequency of the cylinder rotation synchronizing signal 10 and the tape speed are changed in proportion to the frequency of the sampling clock 8, the sampling frequency is changed while keeping relations among the sampling frequency, the cylinder rotational frequency, the tape speed, and the frequency of the cylinder rotation synchronizing signal. Thus, the pitch of recorded or reproduced sounds is changed to fast or slowly reproduce sounds.</p> |
